Methodology - Benthos - MACRO-INFAUNA
Macrozoobenthos Sesile soft bottom fauna, sublittoral - Van Venn grab, with flap covers, 40kg wight, opening 30x30cm, triplicate samples from one sampling point. After collecting the sample, first open the grab onboard, using plastic spade remove gently upper 2cm of sediment into the plastic 5dm3 bucket, wash gently with filtered seawater and sieve on 0,5mm screen. Place the remaining sediment into the washing tray, use gently filtered seawater from the hoose and sieve organisms by flotation on 0,5mm screen. After washing the sample, check large stones and gravel for the presence of sessile organisms, remove clean rocks, and preserve organisms in 4% formaldehyde solution in filtered seawater. In case of substantial amount of sediment left use 10% formaldehyde solution. In the laboratory sample is placed in the plastic container to washout the formaldehyde, and is gently sorted again to remove excess sediment. Organisms remaining on 0,5mm sieve are sorted under the low power stereo microscope. From each sample all macrofauna organisms are sorted, divided into separate jars containing main taxonomic groups. All organisms are counted, for crustaceans the body length is measured for each specimen (tip of rostrum to telson), biomass (wet weight) is established after gently blotting animal (or the whole number of specimens from given taxon) on filter paper and weighted with 0,1mm accuracy. |
 Van
Venn grab |
 Container
for washing sediment samples |
|
 Small box
corer |
 Box
corer - removable box with newly collected sediment |
|
 Camera
and video recording system ready for lowering |
